Figure 6.

Responses to prolonged photostimulation. After 60 minutes of dark adaptation, a subject was exposed to 60 minutes of either a 12.3 log photons cm⁻² s⁻¹ constant light (A) or a 13.3 log photons cm⁻² s⁻¹ stimulus flickering at 2 Hz with a 12% duty cycle (B). In both cases, a total of 15.9 log photons cm⁻² was delivered per trial. Each trace was generated by averaging three trials, and was filtered using a 4-pole low-pass Butterworth filter with a 0.03-Hz cutoff frequency.